Enjoy Reading Afterimages Sometimes we see an object even after we stop looking at it. For example, we can still see the headlights of a car even after we have closed our eyes or the car has turned away. This happens because of afterimages. To see what afterimages are, let's do a simple experiment. Prepare two pieces of paper and a pencil. On one piece of paper, draw a bird. On the other, draw a cage. Then tape each piece of paper, back to back, to the top of the pencil. Now spin the pencil quickly between your hands. If you spin it quickly enough, you can see the bird in the cage. Do you want to know how this happens? When you see something, your eyes send the information to your brain, and your brain understands it as an image. The image stays a little bit longer in the brain than in the eye. This is why you have afterimages. Because of afterimages, if you spin the pencil fast enough in the experiment above, the images of the bird and the cage will blend into one. Afterimages also make animated pictures possible. When you see Peter Pan flying on TV, he isn't actually flying. He is just a drawing on paper. To create the impression of movement, you need many drawings of Peter Pan. Each drawing has to be a little bit different from the one before it. If these drawings are shown to you fast enough, one image blends into the next, and this gives the impression of movement.